A class of proteins now has been identified that is competent to act as true tissue morphogens. That is, these proteins are able, on their own, to induce the migration, proliferation and differentiation of progenitor cells into functional replacement tissue. This class of proteins, referred to herein as “osteogenic proteins” or “morphogenic proteins” or “morphogens,” includes members of the family of bone morphogenetic proteins (BMPs) identified by their ability to induce ectopic, endochondral bone morphogenesis. The morphogenic proteins generally are classified in the art as a subgroup of the TGF-β superfamily of growth factors (Hogan (1996) Genes & Development 10:1580–1594). Members of the morphogen family of proteins include the mammalian osteogenic protein-1 (OP-1, also known as BMP-7, and the Drosophila homolog 60A), osteogenic protein-2 (OP-2, also known as BMP-8), osteogenic protein-3 (OP-3), BMP-2 (also known as BMP-2A or CBMP-2A, and the Drosophila homolog DPP), BMP-3, BMP-4 (also known as BMP-2B or CBMP-2B), BMP-5, BMP-6 and its murine homolog Vgr-1, BMP-9, BMP-10, BMP-11, BMP-12, GDF3 (also known as Vgr2), GDF8, GDF9, GDF10, GDF11, GDF12, BMP-13, BMP-14, BMP-15, GDF-5 (also known as CDMP-1 or MP52), GDF-6 (also known as CDMP-2), GDF-7 (also known as CDMP-3), the Xenopus homolog Vg1 and NODAL, UNIVIN, SCREW, ADMP, and NEURAL.
Members of this family encode secreted polypeptide chains sharing common structural features, including processing from a precursor “pro-form” to yield a mature polypeptide chain competent to dimerize and containing a carboxy terminal active domain, of approximately 97–106 amino acids. All members share a conserved pattern of cysteines in this domain and the active form of these proteins can be either a disulfide-bonded homodimer of a single family member or a heterodimer of two different members (see, e.g., Massague (1990) Annu. Rev. Cell Biol. 6:597; Sampath, et al. (1990) J. Biol. Chem. 265:13198). See also, U.S. Pat. Nos. 5,011,691; 5,266,683, Ozkaynak et al. (1990) EMBO J. 9:2085–2093, Wharton et al. (1991) PNAS 88:9214–9218), (Ozkaynak (1992) J. Biol. Chem. 267:25220–25227 and U.S. Pat. No. 5,266,683); (Celeste et al. (1991) PNAS 87:9843–9847); (Lyons et al. (1989 ) PNAS 86:4554–4558). These disclosures describe the amino acid and DNA sequences, as well as the chemical and physical characteristics, of these osteogenic proteins. See also, Wozney et al. (1988) Science 242:1528–1534); BMP 9 (WO93/00432, published Jan. 7, 1993); DPP (Padgett et al. (1987) Nature 325:81–84; and Vg-1 (Weeks (1987) Cell 51:861–867).
The morphogenic activities of these proteins allow them to initiate and maintain the developmental cascade of tissue morphogenesis in an appropriate, morphogenically permissive environment, stimulating stem cells to proliferate and differentiate in a tissue-specific manner, and inducing the progression of events that culminate in new tissue formation. These morphogenic activities also allow the proteins to stimulate the “redifferentiation” of cells previously induced to stray from their differentiation path. The proteins are useful in the replacement of diseased or damaged tissue in a mammal, particularly when the damaged tissue interferes with normal tissue or organ function, such as, for example, damaged lung tissue resulting from emphysema; cirrhotic kidney or liver tissues; damaged heart or blood vessel tissue, as may result from cardiomyopathies and/or atherothrombotic or cardioembolic strokes; damaged stomach tissue resulting from ulceric perforations or their repair; damaged neural tissue as may result form physical injury, degenerative diseases such as Alzheimer's disease or multiple sclerosis or strokes; damaged dentin and periodontal tissues as may result from disease or mechanical injury.
The proteins have been shown to have utility in repairing a number of non-chondrogenic tissues, including dentin, liver, kidney, neural, cardiac lung, gastrointestinal tract tissue and the like. See, for example, W902/15323, published Sep. 17, 1992; W093/04692, published Mar. 18, 1993; W094/06399, published Mar. 31, 1994; W094/03200, published Feb. 17, 1994; W094/06449, published Mar. 31, 1993; W094/06420, published Mar. 31, 1994. See also, U.S. Ser. Nos. 08/404,113; 08/445,467; 08/432,883; 08/155,343; 08/260675; 08/445,468; 08/461,397; 08/480,528; 08/402,542; 08/396,930; 08/751,227; the disclosures of which are incorporated by reference.
Needs remain for compositions and methods for improved means for evaluating the in vivo activity and/or efficacy of these morphogenic proteins and analogs thereof. It is anticipated that different morphogens will have differing specific activities for effecting morphogenesis in a given tissue or organ. It further is anticipated that analogs of morphogens, including candidate non-protein-based “small molecule” functional mimetics, will need to be evaluated for their ability to functionally substitute for a given morphogen in vivo. It further is anticipated that, for a given indication, such as treating an embolic stroke, for example, dosing and routes of administration can vary depending on the individual's overall health, age and condition. Thus, needs also remain for evaluating the pharmacokinetics of a morphogenic protein or analog thereof, including evaluating dosing, preferred administration times, and preferred administration routes for administering a given morphogen, and/or analog to a given individual, for different therapeutic applications.
Accordingly, it is an object of the instant invention to provide formulations and methods of use thereof for quickly evaluating the in vivo activity of morphogens and/or analogs thereof.
These and other objects, along with advantages and features of the invention disclosed herein, will be apparent from the description, drawings and claims that follow.